Inotuzumab ozogamicin in patients with hard to treat, Philadelphia chromosome-positive acute lymphoblastic leukemia

This study aimed to investigate the effectiveness of inotuzumab ozogamicin (InO; Besponsa) in patients with Philadelphia chromosome-positive (Ph+) relapsed/refractory (r/r) acute lymphoblastic leukemia (ALL). This study concluded that this treatment is a good option for these patients. 

Ph chromosome is a genetic abnormality often found in patients with ALL. Patients with r/r Ph+ ALL have a poor prognosis and limited treatment options. InO combines an immunotherapy with a chemotherapy agent. It is used to treat r/r ALL. However, the safety and effectiveness of InO for patients with Ph+ r/r ALL compared to standard chemotherapy remain under investigation.  

This study involved patients with Ph+ r/r ALL from 2 studies (studies 1010 and 1022). From study 1022, 22 patients received InO and 27 patients received standard chemotherapy (SC). From study 1010, 16 patients received InO.  

In study 1022, the rate of complete remission (CR – no signs of cancer left) or complete remission with incomplete hematologic recovery (CRi) was 73% for the InO group compared to 56% for the SC group. In study 1010, the rate of CR/CRi was 56.3%. 

Minimal residual disease (MRD) is a small amount of cancer cells left after treatment, which is the cause for relapse. In study 1022, of the patients with CRCRi, 81% of the InO group and 33% for the SC group were MRD-negative (no MRD left). In study 1010, all patients (100%) with CR/CRi were MRD-negative.

The average overall survival (OS) was 8.7 months for the InO group compared to 8.4 months for the SC group, in study 1022. In study 1010, OS was 7.4 months. After the 1022 study, patients who proceeded to have a stem cell transplant had longer survival without cancer worsening, regardless of study treatment. 

The most common moderate to severe side effects were liver abnormalities and digestive problems.

This study concluded that InO is an important treatment option for patients with difficult to treat Ph+ ALL.  

This study selected and analyzed patients with Ph+ ALL from 2 different studies. Further studies are needed to be directed at these patients specifically. Also, this study was funded by Pfizer, the manufacturer of InO.